Automatic switch with positive defrost and quick freeze adjustments



Sept. 27, 1938. M. E, HENNINGI AUTOMATIC SWITCH WITH POSITIVE DEFROST AND QUICK FREEZE ADJUSTMENTS 2 Sheets-Sheet 1 Filed May 5, 1934 P 1938- M. E. HENNING 2,131,282

AUTOMATIC SWITCH WITH POSITIVE DEFROST AND QUICK FREEZE ADJUSTMENTS Filed May 5, 1934 2 Sheets-Sheet 2 Patented Sept, 27, 1938 MENTS Malcolm E. He

PATENT OFFICE AUTOMATIC SWITCH WITH POSITIVE DE- FROST AND QUICK FREEZE ADJUST- nning, Des Moines, Iowa, assignor to Penn Electric Switch 00., Des Moines, Iowa, a corporation of Iowa Application May 5, 1934, Serial No. 724,092

2 Claims.

An object of my invention is to provide an automatic switch especially adapted for use in connection with mechanical refrigerators, the switch being comparatively simple, durableand inexpensive to manufacture.

A further object is to provide in a refrigerator switch or the like having defrosting and quick freeze adjustments, a means to positively adjust the switch for either defrosting or quick freezing cycles without such cycles being delayed for sometime after the switch is adjusted to the desired position.

A further object is to provide a defrost and quick freeze adjustable automatic switch of improved characteristics over the switch shown in my copending application Serial No. 699,586, filed November 24, 1933.

Still a further object is to provide a switch or 20 other control device with means for modifying adjacent either limit of its range of movement and to positively secure the operation desired even though automatic mechanism of the control device tends to prevent securing the desired operation.

With these and other objects in view my invention consists in the construction, arrangement and combination of the various parts of my device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawings, in which:

Figure 1 is a side elevation of a control switch structure embodying my invention, parts of the cover for the casing being broken away.

Figure 2 is a front elevation of the same.

Figure 3 is a sectional view on the line 33 of Figure 2.

Figure 4 is a sectional view on the line 4--4 of defrost and quick freezeadjustments can be obtained, the device being adjusted to the normal position.

Figure 5 is a similar view of a portion of Figure 4 showing only the quick freeze mechanism adjusted to the quick freezing position.

Figure 6 is a similar view showing only the parts for defrosting and adjusted to position for obtaining defrosting.

Figure 7 is a sectional view on the line |--I of Figure 3; and

Figures 8 and 9 are perspective views of quick freeze and defrosting elements of the control structure.

n the accompanying drawings, Ihave used the action of an automatically movable member Figure 1 and showing the mechanism whereby' the reference numeral In to indicate generally a switch housing. Within the switch housing in a control arm i2 is pivoted at l4. Movement of the control arm in one direction is opposed by a spring i6, the arm being moved in such direction by a condition responsive means such as a pressure bellows l8, a capillary'tube 2|] and a temperature bulb 22.

The spring l6 in conjunction with the bellows 18 operates the control arm l2 through a given range of movement which can be changed in the ordinary manner as by an adjusting screw 24 rotatably mounted and causing movement of a nut 26 when rotated for changing the tension of the spring.

The spring I6 is seated in a cup washer 28 having cars 30 mounted in notches of the control arm l2. For rotating the threaded rod 24 and thus obtaining adjustment, I provide a gear 32 non-rotatably associated with the rod 24 and meshing with a gear 34. The gear 34 has an extension 36 on which a range adjusting knob 38 is mounted. The knob 38 is located adjacent a face plate 40 having suitable indicia thereon for indicating the tension of the spring iii.

The control arm I2 is adapted to swing a switch arm 42 about its pivot 44. This is accomplished in a snap action fashion by a spring 46 interposed between a point element 48 on the control arm I2 and a similar element 50 pivotally associated with the upper end of the switch arm 42. The switch arm 42 is adapted to slide a contact bar 52 for engaging and separating contacts 54 and 56. The arm 42 has a finger 58 engageable with a slot in the contact bar 52 for sliding it when the arm swings.

D frost and quick freeze mechanism This mechanism is shown best in Figures 4, 5, 6, 8 and 9. A control knob 60 is provided for it and the face plate 40 has suitable indicating characteristics for the (1) normal or non-de-' frosting and non-quick freezing, (2) defrosting and (3) quick freeze positions. The knob 6li'is connected'wtih a plate-like cam 62 which is constrained to remain in the normal position by-a spring 64. The spring 64 has its ends indicated at 66 and 68 crossing each other and spaced on opposite. sides of a stop 10 movable with the cam 62 and a stationary stop I2 extending from a stationary plate 14.

Thus the one spring 64 tends to retain the cam 62 in the central or normal position of Figure 4. and to return it from the quick freeze and defrost positions illustrated in Figures and 6 respectively, as the tendency of the spring 66 is to unwind and the ends 66 and 68 to swing toward each other to the position of Figure 4..

On a pin it, a swinging arm i0 is pivoted. "i" has an enlarged end provided with a slot 82 swingable about a pin 84. tends from the arm it and an anti-friction roller 83 is journalled thereon. The roller 88 normally contacts with a cam surface 89 of the cam 62.

A. sliding lever Elli is pivoted to the pin 86 and has flanges 92 and 9d bent to the position shown in Figure 8 at its lower end. A slot is provided by rabbeting the flange 9d, the bottom of the slot being indicated 96. This slot is adapted to receive an edge of the stationary plate 74 with the portion of the flange 9 3 received in a slot Qt thereof to permit sliding movement, yet position the lower end of the lever Elli with respect to the stationary plate it.

The cam 62 is provided with cam surfaces tilt and M2 in addition to the cam surface 89. The cam surface 89 is formed on a radius from the center of the knob 60 so that a portion of the travel of the cam 62 produces no swinging of the arm is. When the roller 88 is engaged by the cam surfaces I00 and I02, swinging is accomplished however as shown in Figure 5. The opposite end of the slot forming the cam surfaces and indicated at 9!? serves as a reinforcement for the cam plate 62. The flange 92 of the quick freeze lever 90 is adapted to contact with an adjustable stop screw I04 of an'extension I2a of the control arm I2 for a purpose to be hereinafter fully set forth.

Spring tension is provided for the arm I8 and the lever 90 and comprises a perforated ear I06 on the lever 90, a spring bolt I08, an adjusting nut H0 and a spring II2.

The spring connects the adjusting bolt I08 with a stationary pin II 4.

A defrost lever H6 is pivoted at H8, the pivot pin being stationarily associated with the casing I0 of the switch and the stationary plate I4. The defrost lever II 6 has a pin I20 on which an anti-friction roller I22 is journaled. The cam plate 62 has a concentric cam surface I 24 for the roller I22 which at one end terminates in a shoulder I26 and adjacent its other end has a normal position depression I28. Both the depression I28 and cam surfaces I30 and I32 are provided for swinging the lever IIG as shown for instance in Figure 6. The lever H6 has a flange I 34 to engage a stop screw I36 of the control arm I2.

The lever II6 has a perforated ear I38 with which a spring bolt I40 and adjusting nut I42 are associated. A spring I44 is connected with the stationary pin H4 and with the spring bolt I40.

Practical Operation Assuming certain temperatures arbitrarily, if the refrigerator switch has its range and differential adjusted so that it establishes the circuit at 25 and breaks it at 5", there is a range of 20 A pivot pin 86 ex-.

diawly. However, if it has just stopped operating because of the temperature of the refrigerator having been reduced to 5, the additional 10 range is not sufficient to start it operating as the quick freeze adjustment has the effect of bringing the controlling temperature up to 15 rather than to 25 necessary for starting the refrigerator. Therefore, with the switch shown in my copending application hereinbefore referred to, when the normal range of movement is greater than the additional range procurable for quick freezing, the switch would operate as expected when the temperature of the refrigerator is anywhere between 15 and 25 but would not operate when it is between 5 and 15 at the time of adjusting the knob 60 to the quick freezing position. The same holds true at the other end of the cycle for the defrost mechanism.

Accordingly, I contemplate in my present invention a means to positively cause the refrigerator switch tooperate as expected when the knob 60 is adjusted to either quick freeze or defrost positions. This is accomplished when adjusting the knob to quick freeze position by causing the cam surface I02 to positively swing the arm I8 downwardly, thus moving the lever 90 downwardly and causing its flange 92 to move the extension I2a of the control arm I2 downwardly from the position of Figure 4 to the position of Figure 5 if it is not already in its down position.

Similarly, in adjustment to the defrost position, the cam surface I32 positively lifts the roller I22 and swings the flange I34 of the defrost arm II 6 upwardly, causing the extension I2a of the control arm to be raised if it is in its lowered position. Thus the control arm is positively swung to circuit closing position if it is in circuit opening position at the time the control knob 60 is moved to quick freeze position, while it is positively moved from closed position to open circuit position when in the closed position at the time the control knob 60 is moved to the defrost position.

After a quick freeze cycle has been started, the refrigerator will gradually become colder, thus contracting the bellows I8 and permitting the spring I6 to swing the control arm I2 clockwise in Figure 1, thus raising the end In thereof from ,the position of Figure 5 to the position of Figure 4 against the action of the spring I I2, whereby lt takes longer to open the circuit than normally when the tension of the spring H2 is not superposed on the control arm I2 because of the arm I0 being held in raised position as in Figure 4 by the concentric cam surface 89.

Reversely, the spring I44 opposes the spring I6 when the extension In of the control arm moves downwardly from the position of Figure 6 to the position of Figure 4.

The anti-friction roller I22 is provided so that friction caused by the spring I44 tending to cause the upper end of the arm I I6 to engage the cam surface I24 is not imposed as an additional tension when the roller 88 is swung upwardly from the position of Figure 5 to the position of Figure 4 and reversely the roller 88 is provided to eliminate friction as much as possible when the parts move from the defrost position of Figure 6 to the normal position of Figure 4.

The spring 64 for the control knob tends to rotate the cam 62 to its normal position so that any friction with its bearing is not added to the modifying action of the springs II2 and I44.

The depression [28 serves as a means to retain the knob 60 in its normal position in addition to and arrangement 01 the parts of my device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims, any modified forms or structure or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

1. In a control device, a control member movable to two opposite positions, condition responsive means tending to move said control member at times to one 01' said positions and at other times to the other of said positions, means for modifying the action of said control member as afiected by said condition responsive means comprising a pair 01' elements, manually movable means to position one of said elements in position tending to resist movement of said control member to one of said positions and .the other element tending to resist movement of said control member to the other 01' said positions, said ele-- ments each positively moving said control member to the desired position if the control member is, at the time of operation of the element, in the undesired position, one of said elements coacting with said manually movable means to normally tend to retain it in non-operative position.

2. In a control device, a control member movable to two opposite positions, condition responsive means tending to move said control member at times to one of said positions and at other times to the other of said positions, means for modifying the action oi: said control member as aiiected by said condition responsive means comprising a pair of elements and manually movable means to position one of said elements in position tending to resist movement of said control member to one of said positions and the other element tending to resist movement of said control member to the other of said positions, one 01' said elements coacting with said manually movable means to normally tend to retain it in nonoperative position.

MALCOLM E. HEN'NING. 

